AIP: 11 Title: Upgrade of Transaction Protocol Authors: François-Xavier Thoorens fx.thoorens@ark.io, dafty Status: Draft Type: Standards Track Created: 2017-09-25 Last Update: 2019-09-15
In order to move forward with the ARK blockchain for future evolution, the transaction protocol needs to be upgraded. Comment thread: #11
The current status of protocol has several limitations that prevent from future development of services as envisioned on the roadmap:
- impossibility to have cost efficient deserialisation, preventing from scalability of the network
retention-replayattack: a third party can prevent transaction from hitting blockchain inducing the transaction author to create a new transaction. However the transaction is still valid and could be included in the blockchain whenever in the future- impossible to upgrade transactions without hard fork / no support for private transactions
- impossible to scale fees following the market price
- Fast serialisation and deserialisation
- Lay groundwork for future upgrade without the need of a fork
- Able to validate custom private transactions
- Prevent “retention-replay” attack scheme
All numeric values are stored in unsigned little-endian form.
The preferred signature scheme will be Schnorr. Schnorr signatures are fixed 64 bytes long while ECDSA signatures vary between 70-72 bytes. The latter will still be supported just fine, although discouraged.
| Description | Size (bytes) | Example |
|---|---|---|
| header | 1 | 0xff |
| version | 1 | 0x02 |
| network | 1 | 0x17 |
| typeGroup | 4 | 0x01 |
| type | 2 | 0x00 |
| nonce | 8 | 0x00293fa0 |
| sender public key | 33 | 0x025f81956d5826bad7d30daed2b5c8c98e72046c1ec8323da336445476183fb7ca |
| fee | 8 | 0x00000000000e7468 |
| vendorfield length | 1 | 0x0e |
| vendorfield | 0-255 | 0x7468697320697320612074657374 |
| asset | variable | see details below |
Version 0x01 is used for the legacy V1 signature format. Starting at 0x02 all transactions will follow the new signature format and the transaction timestamp will be replaced by a nonce.
See AIP29
A monotonically increasing number derived from the sender wallet.
The asset is defined according to the type of the transaction. This may be changed with a version change in the future.
Type 0 (transfer, 33bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| amount | 8 | 0x8096980000000000 |
| expiration | 4 | 0x04000000 (0x00000000 = no expiration) |
| recipient address | 21 | 0x171dfc69b54c7fe901e91d5a9ab78388645e2427ea |
Expiration is the blockchain height at or after which the transaction cannot be included in a block. In other words, if the block height is equal or bigger than the transaction expiration, the transaction is invalid.
Type 1 (second signature registration, 33 bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| public key of second signature | 33 | 0x025f81956d5826bad7d30daed2b5c8c98e72046c1ec8323da336445476183fb7ca |
Type 2 (delegate registration, 1 + 3-20 bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| length | 1 | 0x10 (minimum 0x03, maximum 0x14) |
| username (utf8) | 3-20 | 0x6669786372797074 |
Type 3 (vote, 34 bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| vote | 34 | 0x0103a02b9d5fdd1307c2ee4652ba54d492d1fd11a7d1bb3f3a44c4a05e79f19de933000380728436880a0a11eadf608c4d4e7f793719e044ee5151074a5f2d5d43cb9066 |
A Vote consists of:
- Vote flag (0x01 if vote, 0x00 if unvote)
- Public key of the delegate
Type 4 (multisignature registration, 1 + 33N bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| min participants | 1 | 0x02 (minimum 0x01, maximum 0x10) |
| public keys | 33*N | 0x03a02b9d5fdd1307c2ee4652ba54d492d1fd11a7d1bb3f3a44c4a05e79f19de9330380728436880a0a11eadf608c4d4e7f793719e044ee5151074a5f2d5d43cb906603a02b9d5fdd1307c2ee4652ba54d492d1fd11a7d1bb3f3a44c4a05e79f19de933 |
Public keys is the concatenation of the public key of all participants of the multi signature wallet.
Limited to a maximum of 16 participants for now.
Also see AIP18
Type 5 (IPFS, 0-255 bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| dag | 0-255 | 0x6669786372797074 |
Type 6 (multipayment, 2-1900544 bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| N payments | 2 | 0x0021 |
| amount1 | 8 | 0x8096980000000000 |
| address1 | 21 | DFJ5Z51F1euNNdRUQJKQVdG4h495LZkc6T |
| ... | ... | ... |
| amountN | 8 | 0x8096980000000000 |
| addressN | 21 | DFJ5Z51F1euNNdRUQJKQVdG4h495LZkc6T |
- N > 1 (ideally fees should be higher than type 0 if N < 2)
- Maximum of possible payments per transaction: 2^16 or 65536. Initially capped to 500 for performance reasons.
Type 7 (delegate resignation)
| Description | Size (bytes) | Example |
|---|---|---|
| No payload | 0 | . |
The sender must be a delegate. Once forged the delegate is irreversibly deactivated:
- no longer possible to vote for this delegate
- no longer treated as an active delegates, regardless of vote balance
Type 8 (htlc lock 66 bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| amount | 8 | 0x8096980000000000 |
| secretHash | 32 | 0x0f128d401958b1b30ad0d10406f47f9489321017b4614e6cb993fc63913c5454 |
| expirationType | 1 | 0x01(network epoch timestamp), 0x02 (block height) |
| expirationValue | 4 | 0x80969800 |
| recipient | 21 | DFJ5Z51F1euNNdRUQJKQVdG4h495LZkc6T |
Also see AIP102
Type 9 (htlc claim 64 bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| lockTransactionId | 32 | 0x025f81956d5826bad7d30daed2b5c8c98e72046c1ec8323da336445476183fb7 |
| unlockSecret | 32 | 0x025f81956d5826bad7d30daed2b5c8c98e72046c1ec8323da336445476183fb7 |
Also see AIP102
Type 10 (htlc refund 32 bytes)
| Description | Size (bytes) | Example |
|---|---|---|
| lockTransactionId | 8 | 0x025f81956d5826bad7d30daed2b5c8c98e72046c1ec8323da336445476183fb7 |
Also see AIP102
see AIP-16 for more detailed information.
A new process will be used where the fee is related to:
- Type of the transaction
- Size of the serialised transaction
The calculation formula is Fee = (T+S) * C
- T: minimum offset byte depending on transaction type, defined by the network (byte)
- S: size of the serialised transaction (byte)
- C: constant (Ark/byte) defined by the delegate including the transaction in his forged block
For instance, for transfer we could have T = 0 byte, C = 0.0001 Ark/byte. For a classic transfer transaction with empty VendorField S = 80 bytes, hence the fee is 0.008 Ark.
For a vote we could have T = 100 bytes, C=0.0001 Ark/byte, S = 82 bytes, fee = 0.0182 Ark
T is here to account for extra processing power to process special transaction whose transfer value is null, and thus reducing economic interest to spam the network.